Optimal Engine / Gearbox Build for long distance?

[Canadian Moke]

Our family of Mokers here in Canada are currently working on the rebuild of three different Mokes.  81 Moke, 82 Cali, 78 Cali.  We are planning a trip across Canada for next summer and are trying to finalize the engine build details.  This trip will be mostly on paved roads but we will also venture off road for some more interesting adventures on route.  This trip will cover approximately 6700kms one way .
 So here are the questions:

Current plan is 1275 engines - probably bored out to 1293 to clean everything up.  Looking at a 255 Cam (I think) in order to get the torque low down in the rev range.  HS6 1 3/4" Carb on TorqueMaster Inlet.  Stage 3 Mini Sport Head. 3 into 1 exhaust manifold & RC40 exhaust.  And everything else re-ground with new bearings.

When we get to the gearbox, we are unsure what final drive to use in order to keep our RPM's low during 8+hours a day on the highway at 110kph, without being unbearable in town, or unusable through mountainous areas.  We are looking to build the engines up to be somewhat efficient as well, but mostly looking to create comfortable rev's for the long days.  You guys have a lot more experience with the long distance travel using the 13" wheels than I do.  Any suggestions from your experience for any part of this build?

Thanks,
Tim.

(P.S. I have already read through pretty well everything I could find on the subject on this site, but none of those posts seem to cover this kind of build.)

[Terry]

Hi,

If the 1275's have even a moderate amount of improved HP or Torque then you should find the 3.7 diff from a Mini is a good compromise and quite 'driveable'.   Most, if not all the 1275' that I travel with have this set up for the long roads and even towing trailers they are good.

The HS6 might be a bit thirsty and with a matching large throat manifold will probably lose you torque. Even on a 1380 I think a HS4 is still acceptable. And in the groups ! travel with we tend to do 100kph or a little less as we aren't all running 1275's and 110 can feel like you are working it all the time and is just a little harder on the economy, but at times we might go a bit harder to get past slower vehicles quickly.

Terry

[Canadian Moke]

Thanks Terry.  I read throughout this board that many of you use the 3.7 diff.  I was wondering if it would be possible to use a lower ratio to bring the Rev's down without giving up to much around town.  We've read through a lot of Visards info on economy and performance and he often suggests the 3.1.  Have you guys tried the 3.1 on any of your longer journey's?

Also, what is it about the larger inlet manifold and carb that you feel would reduce the torque output of the engine?  I already have both parts, but have numerous HS4's as well.  This engine build is still in the 'gathering' phase so changes can be made.

Any input into the ideal Cam for our type of journey?

Thanks again everyone for the input.

Tim.

[Terry]

Hi,

You will notice a 3.7 taking off at the lights in first and there is a rule of thumb around in the diff transmission world I got told of years ago and that is the vehicle has to be be able to move off in first at idle., if it stalls the ratio is too low ... or you need to turn up the idle.

Vizard never drove a Moke , so his thoughts will be all around 10" wheels. I did travel with a 3.4 in a Moke once and it was fine on the flats but in third at the slightest incline.

The problem with going too low is you can move the preferred running speed out of the torque range, meaning that with a 3.1 in topgear a cyclist going past in the other direction will have you changing down a gear. Or if it sees a hill you have to change down. 1275's generally have their torque in the higher revs so shedding too many rev may take away the drive-ability.

The torque is about how much mixture you can squeeze into the cylinder to get the best bang for you bucks, so superchargers/turbos, achieve this by squeezing the air against the valves to create pressure to force the air in when the valve opens. In normally aspirated engine you are relying on atmospheric pressure and the velocity of the air travelling into the cylinder head. You can't change atmospheric pressure so your left with trying to speed up the air which is why the straighter manifolds, like a twin carb set up, will always give better torque than the winding standard manifold style. So that leaves throat and manifold size.

The compromise is between too small an inlet that the engine starves for air and two big a manifold that the air needs a couple of sheep dogs to encourage it to go past the valves. You want to try and have a good air speed so that there is more than just atmospheric pressure at the valves when they open. In your description you aren't talking about a big increase in CC therefore a HS4 on a manifold with a 44mm inlet would be that middle ground. The generic manifolds that can take a HS4 or HS6 are a hindrance with a HS4 because you go from a smaller throat into a larger inlet so your airspeed is killed and it has to speed up again in the last few inches.

I don't really have a view on the Cam, I just tell my cam guy what I want to do and what specs the engine has and he comes up with a number from his head mostly.

You have a bit of time so I would say get your engine ready sooner rather than later and see how it goes on a longer drive and then if you think it needs to change you have time to swap manifolds/carby or even exhaust. I am not sure what choices of 13:" tyres you have but even a higher profile tyres is the difference between a 3.6 and 3.7. An d don't forget to load up for your test drives make sure the suspension can handle the extra weight you will be carrying.

Terry

[FNQ]

Hi Tim
Not comparing apples to apples but i hope my analogy is at least in the same orchard.
I have driven a mini with 13 inch tyres ( low profile though) on a 3000km trip. The mini was a 1310cc, 3.44 diff , 260 degree cam, with twin HS4s set up on # 3 needles ( these were fixed needles -so you may need to find out their swinging equivalents - it is fairly common)


I traversed up to just over 1000 metres above sea level down to sea level, mostly at 100 kph and this was something like 3700 or 3900 rpm.
I was fairly unladen so 600 kg of car, 100 kg of driver and probably less than 100 kg of fuel /gear etc. I needed to give in and change down to third on some long climbs, as the car just wouldn't stay above 70-80 comfortably in fourth, but mostly it was a good drive.
I would bring ear plugs if doing it again. The drone of sitting near 4000rpms for so long in an enclosed cabin was a bit much, but i loved every bit of the bark and wail going through mountain ranges , tunnels and the like.
For me, having to stop every 3hours for 26 litres of fuel ( so about 12km/s per litre) was the biggest chore. ( i immediately installed a RH tank doubling my capacity and have hardly needed it since.)


A single hs4 would have done the job, probably with better economy, but maybe not as many smiles.


In england many minis using 12 and 13 inch low profile tyres  go for 3.1 final drives for their 70mph motorways, but these can gwet caught out getting off at lights especially if uphill- i think if you are going a little offroad you would like a little more drive down below than the 3.1


Anyway i hope this info assists, and as Terry says if possible have some dry runs to test out your combos. Cheers Darryl

[Drakman]

I drove my 1977 Moke down to Melbourne and back last November with my son and the car loaded with our camping gear etc, distance was 3700 klms return.

I have std  sunraiser wheels with 175/70/13 tyres fitted.  The engine has twin HS4 SU's, ported flowed head, 276 cam, 9.5 : 1 pistons and the diff ratio is 3.9 : 1.

The car ran like a swiss watch, (i had to keep getting out to wind it up, lol)

I think we sat on about 105 to 110 klm per hour at around 3900 - 4000 RPM and it went up all but the most severe hills in 4th no worries.

The fuel gauge doesn't work  and the speedo is reading 9 - 10 klms over.  Just so you know.
https://www.youtube.com/watch?v=p6weQMbZGOo

[moemoke]

We used to have a 3.44 in Dynky (13" wheels with 185/65 tyres) with 1275 motor and while it was great for touring on flatish roads
with 1 or 2 people on board it really dies when hitting a hill on the freeway and on longer hills you'd be down to 3rd and with motor screaming.
We now have a 3.7 with 185/60 x 14" wheels it still dies on longer hills (now with 4 people) but cruisers at around 100kph at 3200rpm, there are times when playing off road that a 4.2 would be better.

Is there much elevation change where you are going like mountain ranges to cross etc.
How many people and how much luggage will you be carrying?

[Canadian Moke]

This is the kind of first-hand experience info I was looking for.  Thanks to everyone who has responded so far.  The points about having to downshift at the slightest incline are definitely heard loud and clear.  Part of the trip will see us travelling through the Western Prairies, but right after that comes the Rocky Mountains - many inclines there!  I think we'll go through at least four different mountain ranges on this trip.

Thanks for the clarification on the carbs and torque.  I suppose once I tear down the chosen 1275 I'll now how far it needs to be bored out to clean it all up.  This may help determine the carb size as well.  The 1275's that I have are all un-driven by me (or anyone else for at least the last 20 years).  If the one I go with has had work done in the past, or is deeply scored, I may end up with a larger bore engine than I originally planned.

Everyone's comments seem to point toward the 3.7 diff for this type of journey.  I've been using the The MokeWerx Calculator (https://www.moke.com.au/in-the-garage/workshop-references/75-the-mokewerx-calculator) for some of our figuring and will play a bit more with it based on available tire sizes over here.

In Response to moemoke, we plan to take the best two completed Mokes for the journey and currently have just the three of us going.  So most of the time the Moke will have one or two passengers, but occasionally three for side trips (or three permanently if one of the Mokes suffers something catastrophic). Being Canada though, our spares list is likely to be a bit heavy as parts can be a scarce.  I'm also adding a bit more of a structural roll-cage and twin tanks (long side-fill each side), so the actual weight of my Moke will be up quite a bit.  Good thing each of us are 'right-sized' for Mokes.

On the Cam side of things, my understanding is you want to have the power band within your typical driving rev-range.  Initially we were looking for a cam that put the power band between 1500 and 2500 RPM - when thinking of the 3.1 diff.  With a diff closer to 3.7, I see you guys have used a 260, and a 276.  Any other comments regarding cam experience?

Keep the experiences coming.

Thanks,
Tim.

[Uxmini]

Moemoke,

What cam and carb were/are you using?

Keith

[moemoke]

Moemoke,

What cam and carb were/are you using?

Keith

A water heated inlet with a stock 1 1/5" su carby with standard air cleaner element in a Morris 1100 metal housing, cam is standard as well, it does have some home made 3 into 1 extractors.

What route do you plan on taking, might be interesting for us Aussies to look it up on google maps or street view.

[Canadian Moke]

What route are we taking?  Well, we are still working on the details but basically over the next few years we would like to complete a three oceans tour of Canada.  What three oceans?  Well, the Pacific, Atlantic and the Arctic.  Next summer we plan on dipping our tires in the Pacific and the Arctic.  The general route is attached but we still need to work out a 'dipping' point while we are over near the Pacific.  https://bit.ly/2POtIJe

In the last couple of years they paved the road to Tuktoyaktuk.  It used to be accessible only by Ice Road during the winter months and fly-in in the summer.  My Dad, Keith (UxMini), wanted to take his Moke into the Arctic Circle, but after they 'paved' a road, we figured we might as well make the trip a bit longer and go all the way.  We would take a different route on the way home in order to take in more of the Rocky Mountains and to stop in to the Pacific as well.

We are excited to do the trip and are doing our best to follow all of the advice found on this site and the Mokewerx site regarding preparations for the Mokes.  We figure we will take about 5 weeks to complete the round trip.

We bought the Mokes around Perth, WA back in 2001 and shipped them home.  We shipped a container with 6 Mokes and a 72 Ford Cortina.  The other three Mokes moved on to other owners, but we have kept track of where they are.  After doing a bunch of work on the Cortina, I lost interest and moved it on to another British Car collector.

Keep the comments coming about Vehicle set up.  When I get more organized I will start a post about my 82 Californian (Chuggy) build.

(Edit: Updating the link to show the Canadian Route)

[Terry]

Hi,

is there a reason why you aren't staying on the Canadian side of the border for the start of your trip?

Terry

[Canadian Moke]

We will be staying on the Canadian side.  The map just populated that way.  Often people will go through the states for that section as it cuts down the time and is a bit of an 'easier' drive, but the Canadian section is pretty awesome to check out over the top of Lake Superior.  I should have clicked on the Canadian route before posting the link.  I've made the correction.

Tim.

[Terry]

Hi,

unless I am in rush to get somewhere I always look for the roads with most bends in it as it tends to be more interesting. According to Google it is 200km different but only one hour less.

Are your Mokes converted for right left hand drive?

Terry

[Canadian Moke]

We are leaving them as RHD and we are definitely going to be looking for interesting roads along the way. 

I have attached an outline of Australia overlaid on Canada to show the rough route and provide a bit of scope.

Tim.